Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

Between 2001 and 2011, the percentage of men ages 50 to 64 who were screened for prostate cancer with the prostate specific antigen (PSA) test remained stable, the study found. Screening rates among men ages 40 to 49 increased until 2008, after which they flattened out, but didn't decrease.

Meanwhile, there has been increasing concern over the test's benefit. In 2009, two large studies found that PSA screening leads to a high rate of prostate cancer overdiagnosis — that is, it often finds cancers that would not have gone on to cause problems or death in a man's lifetime. These studies were widely covered by the media at the time, and eventually led to changes in PSA screening recommendations.

For instance, the American Cancer Society changed its recommendations in 2010 to say that men should speak with their doctors about the benefits and risks of PSA screening starting at age 50 (earlier guidelines had recommended yearly PSA screening). And the U.S. Preventive Services Task Force recommended against PSA screening in late 2011.

The new findings suggest that, once screening is recommended, it's hard to go back on that advice.

For three decades, "The message has been 'get screened, get screened, get screened,'" said study researcher Dr. James Goodwin, director of the Sealy Center on Aging at the University of Texas Medical Branch in Galveston. "We were very, very successful in getting that message across," Goodwin said. "And then we can't just suddenly say 'stop.'"

Goodwin said he suspects it will take a while to get the new message across, but that there will be a gradual change as even more research is published.

The new study is based on records from a private health insurance database, which included information from more than 1.5 million men yearly.

In 2001, PSA screening rates were 12.1 percent for men ages in their 40s, 32.7 percent for men in their 50s and 42.7 percent for men ages 60 to 64. In 2011, screening rates were 15.7 percent, 34.2 percent and 42.0 percent, for each respective age group.

Because the U.S. Preventive Services Task Force changed its recommendation in late 2011, the effect of that change may not be reflected in the new study. However, Goodwin said that changes to medical practice can occur quickly, within days of media coverage of a new study.

Many experts believe a practice known as active surveillance could reduce unnecessary treatment of the disease. Under active surveillance, patients diagnosed with low-risk prostate cancer receive regular follow-up testing, and are treated only if their cancer becomes more aggressive.

But Goodwin said that in his experience, patients want to take action once they hear the word "cancer," rather than wait, even if that cancer isn't going to cause harm. "Many men do not tolerate that concept," Goodwin said, referring to active surveillance. "The word 'cancer' has such an emotional weight."